In one specific aspect, the invention provides such constructs that can be used as “artificial” or “synthetic” antigen-presenting cells (for example, as “artificial” or “synthetic” dendritic cells). In this aspect, the constructs of the invention can, in particular, be used to present one or more antigens to one or more T-cells (either in vitro, ex vivo or in vivo); to activate, to inhibit and/or to modulate (one or more immunological activities of) one or more T-cells and/or to otherwise interact with one or more T-cells (again, either in vitro, ex vivo or in vivo); and/or other cells of the immune system that recognize specific antigens such as B-cells or NKT-cells or NK-cells; and/or generally to induce and/or to enhance an immune response against a desired antigen in a subject to be treated (or alternatively, to suppress such an immune response, as further described herein). Again, in this aspect, the constructs of the invention can be used for immunotherapy (for example, of cancer) and for other immunological applications, as further described herein.
The invention further relates to methods for preparing the constructs described herein, to pharmaceutical compositions that contain one or more constructs of the invention, to applications and uses of such constructs and of such compositions, and also to the use of a pharmaceutically acceptable helical polymer (as further described herein) in preparing the constructs of the invention.
Other aspects, embodiments, features, applications, uses and advantages of the invention will become clear from the further description herein.
Generally, unless explicitly defined otherwise herein, the terms used in this specification have their usual meaning in the art (being the art of immunology for all immunological terms, the art of protein chemistry for all terms relating to protein manipulation and chemistry, and the art of polymer science for all terms relating to the description and manufacture of polymers), for which reference is made to the handbooks and review articles cited herein. Also, all methods and techniques that are not described in detail in the present application can be performed using standard techniques in the field of immunology, protein chemistry or polymer science, respectively, for which reference is again made to the handbooks and review articles cited herein.
Also, generally, the constructs of the invention that contain a pharmaceutically acceptable helical polymeric carrier (as described herein) and one or more (and usually two or more) proteins, peptides, factors, subunits, binding units or other compounds or biological moieties (also as described herein) will also be referred to herein as “constructs of the invention.” The proteins, peptides, factors, subunits, binding units or other compounds or biological moieties that may be present in the constructs of the invention are also collectively referred to herein as “components” of the constructs of the invention. The pharmaceutically acceptable helical polymer that is present in the constructs of the invention is also referred to herein as the “polymeric backbone.”
Immunotherapy can generally be described as the treatment of a disease by inducing, enhancing or suppressing an immune response, e.g., in a subject to be treated. Generally, the active agents used in immunotherapy are referred to as “immunomodulators” or having an “immunomodulatory” action or effect. Reference is, for example, made to the following handbooks and review articles: Parham, The Immune System, 3rd edition, Taylor and Francis, 2009; Roitt's Essential Immunology, 11 th Edition, Peter Delves (University College London), Seamus Martin (Trinity College, Dublin), Dennis Burton (The Scripps Research Institute, CA), Ivan Roitt (Royal Free & University College Medical School); Janeway's Immunobiology, Seventh Edition, Kenneth M. Murphy, Paul Travers, Mark Walport, as well as the further references cited therein.
For example, despite significant advances in conventional therapies (surgical procedures, chemotherapy and radiotherapy), the prognosis for multiple types of cancer remains low and recurrent disease often develops in advanced-stage cancer patients. Anti-cancer immunotherapy represents a promising strategy, as it is designed to specifically activate the immune system to eradicate tumor cells. The importance of the immune system in controlling tumor growth is demonstrated by the higher survival of patients with intratumoral T-cells compared to patients without intratumoral T-cells (Zhang et al., N. Engl. J. Med. (2003) 348:203-213).
One form of immunotherapy involves the use of dendritic cells or “DCs” (or other suitable antigen-presenting cells or “APCs”) that have been modified (for example, loaded with an antigen against which an immune response is to be raised) so as to allow them to achieve a desired immunological or biological effect (for example, raising or enhancing an immune response against a desired antigen, such as an antigen that is expressed by a tumor to be treated), often via the naturally occurring antigen-presenting interaction between the APCs and T-cells, which, in turn, leads to activation of the T-cells and to an immune response against the antigen.
Very generally, this interaction between APCs and T-cells can be said to be primarily mediated by the interaction of a major histocompatibility complex or “MHC” (which presents the antigen to the T-cells in the form of an MHC-antigen complex) on the surface of the APC and a T-cell receptor or “TCR” on a T-cell. However, it is also well known that a number of other co-stimulatory factors, signals and interactions (such as the interaction between CD80/CD86 on APCs with CD28/CTLA-4 on T-cells) and other immunomodulatory peptides and factors (such as, for example, cytokines and chemokines) also play an important role in the interaction between APCs and T-cells (and, more generally, in activating, enhancing or modulating T-cell activity and/or immune responses against an antigen), often working as a “second signal” to the T-cell. The term MHC in this context is herein defined as molecules capable of presenting antigen to T-cells.
It will also immediately be clear to the skilled person that these interactions between the MHC-antigen complex on the APC and the TCR on the T-cell, as well as the interaction between co-stimulatory factors on APCs and their receptors on a T-cell, are just two of the more important interactions between APCs and T-cells, and generally form part of a larger complex of signaling, factors and interactions that are involved in antigen presentation, in the interaction between APCs and T-cells generally, in T-cell activation/modulation and/or in raising an immune response against an antigen. For a detailed description of the same, reference is, for example, made to the handbooks and review articles mentioned above in the paragraph on immunotherapy as well as the further references cited therein. Reference is, for example, also made to Huppa et al., Nature (2010) 463:963-967.
Similarly, it is known that APCs can stimulate natural killer T-cells (“NKT cells”), a group of T-cells that share properties of both T-cells and natural killer cells, but that recognize lipid and glycolipid antigens (presented by CD1d molecules) rather than peptide antigens presented by MHC complexes (see, for example, Melián et al., Curr. Opin. Immunol. 8(1):82-8 (1996); Brigl and Brenner, Annu. Rev. Immunol. 22:817-90 (2004); and Martin et al., Proc. Natl. Acad. Sci. U.S.A. 83(23):9154-8 (1987).
For a further description of the use of DCs in immunotherapy, reference is made to the following handbooks and review articles: “Dendritic cell immunotherapy: mapping the way,” Carl G Figdor et al., Nature Medicine 10:475-480 (2004); and “Taking dendritic cells into medicine,” Steinman and Banchereau, Nature (2007), Sep. 27, 449(7161):419-26, as well as the further references cited therein.
The use of live DCs in immunotherapy (or generally in raising or modulating an immune response in a subject), although highly successful as therapy, has a number of practical disadvantages, the main one being that live DCs have to be harvested from the subject and/or differentiated in vitro from precursor in order to be loaded, ex vivo, with the desired antigen(s) and then have to be placed back into the subject. Apart from also being cumbersome and expensive because of the extensive safety requirements (GMP/GLP), these techniques also have the usual limitations that are associated with working with living cells, such as limitations as to time (depending on how long the DCs can be kept viable outside the body of the subject) and as to scale (which can generally be said to be limited to laboratory scale without major scale-up being feasible); and also are subject to the variability that is inherent when working with living systems. Furthermore, whereas live DCs need to be autologous due to HLA restriction and host-versus-graft rejection, synthetic APCs are applicable to every patient.
For this reason, the art has been looking for alternatives to the use of live DCs in immunotherapy. One such alternative involves the use of “artificial” or “synthetic” DCs, i.e., protein-based constructs that are designed to mimic one or more of the properties and immunological effects of DCs, in particular, when it comes to presenting antigens to T-cells and/or to inducing or stimulating T-cells. Generally, such artificial antigen-presenting cells comprise a suitable carrier (for example, spherical-shaped structures such as magnetic beads, latex beads or poly(lactic-co-glycolic acid) (PLGA) microparticles) to which are attached one or more proteins, peptides or factors that can, for example, present antigen to T-cells (such as suitable MHC-antigen complexes), that can induce or stimulate T-cells (such as co-stimulatory factors, for example, those naturally occurring on APCs), and/or that can generally improve or enhance the binding and/or interaction between the synthetic APCs and T-cells and/or provide a desired immunomodulatory effect. Reference is, for example, made to Steenblock et al., Expert Opin. Biol. Ther. (2009) 9:451-464; Chang, Exp. Mol. Med. (2006) 38:591-598; Lu et al., Cancer Immunol. Immunother. (2009) 58:629-638; Oelke et al., Nat. Med. (2003) 9:619-624; and Zhang et al., J. Immunol. (2007) 179:4910-4918; J. Greensmith and U. Aickelin (2009), “Artificial Dendritic Cells Multi-faceted Perspectives” (PDF), in Human-Centric Information Processing Through Granular Modelling: 375-395; Steenblock et al. Molecular Therapy (2008) 16(4):765-772; Chang et al. Experimental and Molecular Medicine (2006) 38(6):591-598; Maus et al., Clinical Immunology (2003) 106:16-22; Rudolf et al., Cancer Immunol. Immunother. (2008) 57:175-183; Goldberg et al., The Journal of Immunology (2003) 170:228-235; Caserta et al., Cancer Research (2008) 68(8):3010-3018, as well as to, for example, to U.S. Pat. No. 6,787,154.